Found this hotkey (Windows) by accident and it's my new favorite thing ever. WindowsKey+P brings up a video quickswitch where you can toggle V1, V2, Duplicate or Extend in one move. It. Is. Glorious. Now if I could switch my audio as easily I'd be set.
(I have my computer in one room, and video and audio outs going through the wall to my living room TV. So when I'm switching this turns a 2 minute ordeal with the mouse and screen resets and confirmations into a single click on the keyboard while the tv turns on. "and many a woot was had that day."